Columbia is joining a long list of U.S. cities taking another look at the decades-old practice of adding fluoride to public drinking water.

It’s a debate that has resurfaced from time to time across the country over the past several decades. In recent years, the practice has come under fresh scrutiny from activists armed with research challenging the government’s claim that ingesting fluoride is a safe way to control tooth decay. Among the studies are some linking excessive fluoride intake with adverse effects on public health, such as an increased likelihood of bone fractures or linking the ingestion of fluoridated water to lower IQ among children.

Prompted by a group of residents who have been publicly calling for an end to fluoridation, the Columbia City Council has asked the Columbia Board of Health to research the issue and make a recommendation.

“It warrants a second look to see if ingesting fluoride is really the best way to go at this,” said Sixth Ward Councilwoman Barbara Hoppe, who drinks bottled water that does not contain fluoride.

Some fluoride opponents, including Columbia resident Bruce Summers, who spoke against fluoridation at a council meeting this month, take issue with the fact the government is administering a medication through public water without consumers’ consent and without controlling the dosage.

“Could you imagine a doctor suggesting that we add vitamin D or iron or even aspirin to the water supply?” Summers asked the council. “They’d lose their medical license.”

City officials have taken a neutral stance on the issue. If the city council decides the public’s drinking water should be fluoride-free, administrators say the roughly $50,000 spent on it each year could easily be spent elsewhere.

But supporters of fluoridating public water — including the U.S. Centers for Disease Control and Prevention, the American Dental Association and the World Health Organization — maintain that appropriate levels of fluoride in public drinking water have positive effects on public health. Some organizations argue that removing fluoride from water could disproportionately affect low-income families who cannot afford proper dental care. The CDC even says fluoridating public drinking water was one of the most significant contributions to public health in the 20th century.

In the weeks since local residents began to petition the city for removal of fluoride from the water system, the Tribune has received unsolicited letters from nationally based organizations defending the practice.

The Pew Children’s Dental Campaign, a project of the Pew Charitable Trust, issued a memo Tuesday disputing claims from anti-fluoride activists and asserting that while it might be tempting for local governments to end fluoridation to shore up their budgets, governments might have to pay more in the future if it places additional strain on public health programs because of increases in tooth decay.

“State and local budgets are under serious strain,” the memo says. “The desire to cut spending has made some elected officials receptive to activists who contend that discontinuing fluoridation will save their community money. However, the evidence shows that the opposite is true.”

CONSPIRACY OR COVER-UP?

Fears about fluoridating public water were famously lampooned in the 1964 film “Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb,” in which a U.S. general has gone rogue from his country and remarks that he felt “fatigue” and “emptiness” during an act of “physical love.”

The general chalked it up to Soviets putting fluoride in the drinking water, which he called a “monstrously conceived” plot to pollute Americans’ bodies. The plot takes aim at real-life 1950s propaganda spread by anti-communist groups claiming that water fluoridation was part of a secret plot to make Americans docile and easier to control.

Jeffrey Pasley, an associate history professor at the University of Missouri who has taught a course on conspiracy theories, said water fluoridation concerns have evolved to “mimic serious social cause advocacy” but still maintain the basic hallmarks of classic conspiracy theories — namely mistrust of large institutions and fears about what’s in the water.

“It’s easy to get people cranked up about this notion that there are poisonous substances in your water,” he said.

But anti-fluoridation activities say that early fear- mongering about the evils of fluoridation are doing a disservice today for those working to better inform the public about what they are drinking. Paul Connett is an environmental chemistry professor at St. Lawrence University in Canton, N.Y., and director of the Fluoride Action Network, an international group that seeks to raise awareness about fluoride. Talk of Strangelove and tin-foil hats by journalists and those who support fluoridation makes him want to “explode,” he said.

Connett co-authored a 2010 book titled “The Case Against Fluoride: How Hazardous Waste Ended Up in Our Drinking Water and the Bad Science and Powerful Politics That Keep It There.” In the two years since, he said, he has not seen a “serious scientific critique” of the claims he and two other researchers presented in the book. Instead, fluoridation proponents seem to all-too-quickly reach for the argument that the CDC considers fluoridation a boon for public health.

“This is utter nonsense, but they get away with it,” Connett said. “They get away with it because they, quote, have the authority.”

In a report released in 1999, the CDC said it considered water fluoridation to be one of the top 10 contributions to public health in the 20th century. That same report said no subsequent research supported association between fluoride and increased risks of cancer, Down syndrome, bone fracture, Alzheimer’s disease or other health conditions. To support the claim, the report’s author cited a study from 1993, six years before the CDC report was released.

Connett said if he used material six years out of date to support his anti-fluoride claims, “I would be crucified.”

He also points to a 2006 study from the National Research Council about the effects of high levels of fluoride in drinking water. At 4 parts per million — the maximum allowed by the U.S. Environmental Protection Agency — children could be at increased risk for dental fluorosis, a disorder that affects the way enamel develops and can cause spots on teeth. The same report also says that level of fluoride could cause weakened bone structures and lead to bone fractures.

In 2011, the U.S. Department of Health and Human Services recommended the amount of fluoride in public drinking water systems be lowered from a maximum of 1.2 parts per million to a maximum of 0.7 parts per million, which is the level found in Columbia’s drinking water. Of that amount, about 0.3 parts per million of fluoride is naturally occurring.

Fluoridation opponents often cite this change as evidence that the government is acknowledging the dangers of fluoridated water. But supporters, including Lori Henderson, a local pediatric dentist, say that the recommendation takes into account the fact there are more fluoride sources, such as toothpastes and mouth rinses, available today than when the original recommendation was set.

Henderson, who also serves as the state’s public policy advocate for the American Academy of Pediatric Dentistry, said the science behind fluoridation should continually be reassessed. But since she started practicing dentistry in 1979, the issue has continually resurfaced, she said, and experts continually say that the benefits of fluoridating public drinking water outweigh the risk.

While some opponents are “unnecessarily frightened” by the idea of fluoridated water, Henderson supports the idea of bringing the issue to a public vote.

“I don’t have a vested interest in continuing a practice that, in light of newer studies, would prove to be deleterious,” she said.

When asked about claims that fluoridation amounts to involuntary medication of the public, Henderson related the issue to mandatory vaccinations, which are administered to young children. She said it is the “responsible thing” to provide children with treatments that they might not normally seek out themselves.

“Individual rights, at some point, coincide with the good of the community,” Henderson said.

OTHER CITIES IN LIMBO

Since 2010, the year Connett’s book was published, 79 cities in the United States, Australia, Canada and New Zealand have eliminated fluoride from drinking water, according to the Fluoride Action Network’s website. The website notes that 97 percent of western European countries do not fluoridate public water, but many of those countries add fluoride to table salt.

In Missouri, cash-strapped Pevely, which is south of St. Louis, decided this year to stop fluoridating its water to save money. In O’Fallon, which stopped putting fluoride in public water in 2010, officials touted the end of the practice as a way to save money and enhance worker safety. Earlier this year, St. Joseph’s city council cast a split vote in favor of continuing to fluoridate its water.

The debate is not coming from one side of the political spectrum.

The seven-member Pinellas County, Fla., Board of Commissioners voted to put fluoride in its water in 2004 after years of being known as the largest water supplier in the eastern United States to not fluoridate its water. John Morroni, a Republican county commissioner who once supported the practice, has been credited for spearheading an effort to end water fluoridation, saying it amounted to government overreach. Last year, commissioners voted to end fluoridation.

But many Pinellas County voters did not agree, and the fluoride issue took center stage in local politics this year, according to the Tampa Bay Times. Two Republican commissioners who voted in favor of ending fluoridating lost re-election and blamed the fluoridation issue.

Kenneth Welch, who was the sole Democrat on the Pinellas County board before the November election, said the anti-fluoridation push came from a group of “ultra-conservative activists.” Those who supported fluoride in the water, he said, included local business groups concerned that the county would miss out on economic development opportunities if it were perceived as being out of touch with modern science, he said.

“I think it kind of gave Pinellas County kind of a black eye in terms of competing for jobs,” Welch said.

Pinellas County has more registered Democrats than Republicans but typically supports Republicans in local races.

In Portland, Ore. — where President Barack Obama won 75 percent of the votes — the city council voted earlier this year to start adding fluoride to the water by 2014. But anti-fluoride activists, mainly through the group Clean Water Portland, collected more than enough signatures to put the decision to voters in May 2014.

Rick North, a member of the group’s executive committee, served as executive vice president for the American Cancer Society in Oregon about five years ago when he was first asked to research fluoridation. Until that point, he said he’d had no doubt that fluoride was beneficial to humans.

But the more North read, the more alarmed he became. He said it was hard to trust the government’s line on water fluoridation after reading the 2006 NRC study recommending that the EPA lowered the maximum amount of fluoride it allows in public drinking water. And, he said, he became unsettled by the fact that fluoride is being administered to people who did not give consent to receive it.

“This is about way more than teeth,” North said. “This is about human health and a drug being added.”

Portlanders should be more alarmed by the amount of tooth decay in the city, particularly among the poor, countered Mel Rader, co-director of Upstream Public Health in Portland and a coordinator for the Everyone Deserves Healthy Teeth Coalition.

“This is a social justice issue,” Rader said. “You go to rich neighborhoods, their teeth look great. You go to a poor neighborhood, their teeth look terrible.”

KEEP COLUMBIA FLUORIDATED?

Columbia has been fluoridating its public drinking water since 1973, according to Tribune archives. The decision was made by Don Allard, the city manager at the time. There is no record of the city council voting on the issue, said to City Clerk Sheela Amin.

While any debate over adding fluoride was absent from the headlines, there was some disagreement about the practice. In April 1976, J.F. Keough of St. Charles wrote a letter to the editor of the Tribune saying he took issue with a proposed state bill that would have mandated fluoridation of water systems statewide. Keough, a member of the St. Charles Fluoridation Study Committee, wrote that scientific studies from the 1950s indicated that, over time, fluoridated water acts as a “body-cell enzyme-poison” and that studies from the 1970s found fluoridated water had some cancer-causing properties. Voters in St. Charles and Washington voted down fluoridation proposals in 1971 and 1972, respectively.

“Wherever the issue is proposed and open to public view, it will be defeated by intelligent voters,” Keough wrote.

A few days later, the Tribune published another letter from Columbia resident Charles Atkins, who wrote that fluoridated water was the best way to help those who could not afford to pay for dental care. Atkins also expressed frustration with anti-fluoride groups that generated “fear and controversy” when he worked with citizen groups in southeast Missouri to promote fluoridation.

In fiscal year 2012, the city of Columbia purchased fluorosilicic acid from The Mosaic Co., a Plymouth, Minn.-based agricultural products firm that generates the substance as a byproduct of fertilizer production. The company has told the Tribune that its sales of fluorosilicic acid are “non-material” when considering the company’s entire balance sheet.

According to the company’s annual report for its 2012 fiscal year, which was submitted to the Securities and Exchange Commission, fluorosilicic acid is produced in facilities in Florida and Louisiana, and the report warns that an accident involving this or other hazardous chemicals at the company’s facilities could not only cause injury or death to humans but could also hurt the company’s bottom line.

The Columbia Board of Health is expected to discuss fluoridation at its Jan. 10 meeting. Board member Colin Malaker, a local dentist, said he is still researching the issue. As a libertarian, he said he has issues with the administration of fluoride through public water but doubts governmental and health agencies are lying to the public when they claim appropriate levels are safe.

Either way, Malaker said, no amount of fluoride in the public water supply will make up for basic oral hygiene when it comes to fighting tooth decay.

“You could fluoridate the water all day long,” he said. “If you don’t brush your teeth, it isn’t going to work.”